let the number of nickels be x, the number of dimes is x+8 but 1 nickel=$0.05 1 dime=$0.1 thus, the total amount Susan has will be: 0.05x+0.1(x+8)=3.05 0.05x+0.1x+0.8=3.05 0.15x=2.25 x=2.25/0.15 x=15 thus the number of nickels is 15 number of dimes is 15+8=23